During a recent 4-month period we studied 2 patients who died shortly after operative "repair" of either tetralogy of Fallot or double outlet right ventricle, both with subpulmonic obstruction, and necropsy in each disclosed that a major epicardial coronary artery had been inadvertently severed at operation. Because neither patient had had coronary angiography preoperatively and because death in each appeared to have resulted from the transection of the major coronary artery, a brief summary of each patient appeared warranted as a springboard from a discussion of the rationale of coronary angiography before operative "correction" of complex congenital heart disease.